Metadata is information about the file. Normally the camera you used to take the photo will put in metadata. However, in this case, unless your camera can take 360 degree panoramas (mine can't), then you need to change the metadata.

In your second link, http://photoshopcafe.com/facebook-360-panorama-VR it is explained exactly how to do that. Go to 8 minutes in the video to find that information. He explains that you can either use the template he provides -- you would paste you image into his template -- or you can go to a web site to add the meta data.